In Apex 5, apparently one has to be a Workspace Administrator to alter or create users. Is there a workaround that actually works so that regular users can do things like reset passwords and create users? I tried both the scheduler trick and API checkoff and none of that works. I've even granted every database user APEX_ADMINISTRATOR_ROLE and APEX_GRANTS_FOR_NEW_USERS_ROLE and nothing seems to work. I am still getting ORA-20987 requires ADMIN privilege to perform this operation.
This is very annoying and will keep me from using anything above APEX 4.XX in the future.
The scheduler stuff I copied from was here:
Using APEX_UTIL to create users from APEX page
Which still gave me the same error!
The checkoff item I did was already posted in a bunch of places: Like here:
authentication - Oracle apex issue - ORA 20987: APEX - User nobody requires ADMIN privilege to perform this operation. -…
I have all three boxes checked off (not just the bottom one, but I have tried checking just the bottom one).

So at this point, I'm stumped!
I am using APEX 5.0.3.00.03 with Oracle Database 12c Enterprise Edition Release 12.1.0.1.0 - 64bit Production